Introduction: The Autism Spectrum Disorders (ASDs) have onset in the first years of life and are characterized clinically by qualitative impairments in social interaction, communication and a restricted repertoire, stereotyped and repetitive interests and activities. Currently there is a medical consensus on the causes of autism: they should not be psychosocial but should be based in biology, especially in the central nervous system abnormalities caused by both inherited and environmental causes. The aim of this study was to study a sample of subjects with Autism Spectrum Disorders (ASDs) with a wide protocol, including neurophysiological and radiological investigations as well as laboratory investigations in order to investigate the neurobiologic basis of the syndrome. Methods: The patients group included 34 subjects diagnosed as having ASDs. All were examined with a protocol of investigations (brain MRI; EEG; VEP, ABR; karyotype; evaluation of brain metabolites; antibodies against neurotrophic agents). In order to evaluate and identify the presence and intensity of autistic symptoms have been used the CARS (Childhood Autism Rating Scale) and ADOS (Autism Diagnostic Observation Schedule) tools. Results and Conclusion. Ninety percent of the subjects had at least one parameter neurobiological disease, the fifty-nine percent have a specific genetic syndrome. This study highlights the different noxae involved in the etiopathogenesis of AD and the percentage that every biological factor has in the development of the autistic phenotype. This study confirms the hypothesis that autism spectrum disorders (ASDs) are a severe neuropsychiatric diseases with strong genetic basis
